Pyrotechnic device for destruction of valuable documents

ABSTRACT

A pyrotechnic device for destruction of valuable documents in which a primary incineration charge and a propellant charge are electrically triggered by an external signal, and an extinguisher charge is triggered when a precise portion of the propellant charge is consumed.

FIELD OF THE INVENTION

This invention relates a device for destruction of valuable documents and more particularly to a pyrotechnic device for destruction of valuable documents which is capable to destroy efficiently the documents contained therein, independently of the amount and/or thickness.

BACKGROUND AND PRIOR ART

Prior pyrotechnic based techniques for the rapid and reliable destruction of valuable documents are severely limited in the thickness of the document stack which they can reliably destroy. Protection systems based on prior art which are intended to destroy large quantities of notes therefore require multiple pyrotechnic charges and their associated multiplicity of ignition systems and circuits. They also require that large stacks of documents be split into many smaller stacks in order not- to exceed the maximum thickness constraint.

Documents to be potentially destroyed are more conveniently arranged in large piles or stacks however, whether for storage, transport, or in particular in automated handling and teller systems.

DESCRIPTION OF THE INVENTION

A device for the rapid and controlled destruction of a large number of valuable documents is described. The device comprises a primary incineration charge, a propellant charge and an extinguisher charge. The two former are electrically triggered by an external signal, and the latter is triggered once a precise portion of the propellant charge has been consumed. In addition to the charges, the device includes electrically triggered igniters and initiators, a fully-sealed long lifetime battery, fully-sealed trigger reed switches, and associated circuits and wiring.

The primary destruction mechanism is by high-temperature incineration, caused by well known, localized, Metal/Metal-Oxide exothermic redox reaction. The invention utilizes a single composite pyrotechnic charge and housing to destroy a specific portion of every document in a stack. Since the design is linearly scalable to arbitrary limits, only one charge is required for any number of stacked documents. This is in contrast to existing thermite torch based systems, which are limited in the maximum thickness of the stack that can be satisfactorily and reliably destroyed. The present invention thus has a wider field of application, as well as offering considerable cost savings, in comparison to existing methodologies.

The main incineration charge is housed within a rectangular section metal tube (A). The side of the tube which will face toward the document stack has an opening (B) along that part of its length corresponding to the maximum length of the document stack to be destroyed. This opening is covered with a thinner metal or plastic burst sheet (C), which seals and protects the charge before deployment. The incineration charge is contained within the rectangular tube, and comprises separate igniter/initiator/propagation layers (D) laminated with the primary high-temperature redox components (E). The primary charge tube is fixed inside a metal/refractory material housing (F), and retained in position with heat-sensitive release beads (G). A solid propellant charge is enclosed within the volume formed between the housing and the charge, and held in place either by a spring clip, by conventional adhesive, or by the technique of casting in place. One end of the propellant charge is equipped with a conventional electric-match type igniter device (not shown, for clarity).

In operation, the primary incineration charge and the propellant are simultaneously ignited when the trigger signal energizes reed relay solenoids, causing them to dose.

Battery power is then supplied to both the propellant igniter and the main charge igniters/propagators.

The increase in temperature from both the primary charge and the propellant exhaust gases cause the thermal release beads to activate, allowing the main primary charge to move into contact with the documents. The increasing pressure from the propellant forces the primary charge unto the document, and the high temperatures generated by the charge destroy them. A conventional relay fuse placed near the end (i.e. the last portion to be consumed) of the propellant charge then triggers a Nitrogen generating charge to suppress fire propagation within and from the destroyed documents.

Naturally, the invention is not limited to the embodiment describe above, other alternative forms whereof can be provided without departing thereby from the scope of the attached claims. 

1. A pyrotechnic device for destruction of valuable documents comprising: a primary incineration charge; a propellant charge, and extinguisher charge; wherein the primary incineration charge and the propellant charge are electrically triggered by an external signal, and the extinguisher charge is triggered when a precise portion of the propellant charge is consumed.
 2. A device according to claim 1, including a multiple-stage igniter which comprising at least one electrically fired initiators, a rapid flame propagation layer and one or more discrepant repeater charge.
 3. A device according to claim 1, further comprising a release mechanism of charge which is thermally activated, allowing said device come into intimate contact with the stack of documents to be destroys, and maintaining a minimum spacing between them to facilitate free movement of the stack.
 4. A device according to claim 1, further comprising a housing which serves as both a heat shield for objects other than the stack to be destroyed, and as a semi-sealed volume within which a propellant charge is drive on the documents to be destroyed.
 5. A device according to claim 4, comprising a propellant charge contained a chemically stable Potassium Nitrate/Sorbitol solid, wherein the effectiveness in destruction of the documents is controlled by setting of the dimension of the charge and its chemical composition.
 6. A device according to claim 4, wherein said effectiveness in destruction of the documents is controlled by coating selected surfaces with combustion-inhibiting.
 7. A device according to claim 4, wherein the controlled burn-rate propellant is used as a timing device for sequenced ignition and deployment of a pyrotechnic fire-suppressant system.
 8. A device according to claim 4, comprising a Nitrogen generator charge capable of depleting the ambient Oxygen concentration in the vicinity of the destroyed document, suppressing propagation of fire throughout and beyond the documents.
 9. A pyrotechnic device according to claim 4, wherein electrical triggering system using a long-lifetime hermetically sealed battery, where both poles are connected via minimum length low-leakage sealed conductors to sealed vacuum reed switches. 